Method and Apparatus for Transmitting or Receiving System Information in Wireless Communication System

1. A method for receiving system information by a User Equipment (UE) in a wireless communication system, the method comprising: receiving a message including information associated with allocation of a downlink resource with an Uplink Channel Description (UCD)/Downlink Channel Description (DCD) count from a base station; receiving changed system information through the allocated downlink resource when the UCD/DCD count is greater than a UCD/DCD count stored in the UE; and receiving a downlink data through the allocated downlink resource when the UCD/DCD count is the same as the UCD/DCD count stored in the UE, wherein the message is transmitted at the beginning of a listen interval of the UE.

2. The method according to claim 1 , further comprising: comparing a UCD/DCD count value included in the message including the information associated with allocation of the downlink resource and a UCD/DCD count value stored in the UE and determining whether or not the system information has changed.

3. The method according to claim 1 , further comprising: transmitting negative-acknowledgement (NACK) information to the base station and receiving the changed system information from the base station, if the UE fails to receive the changed system information.

4. The method according to claim 1 , wherein the changed system information is included in an Uplink Channel Description (UCD) message or a Downlink Channel Description (DCD) message.

5. The method according to claim 1 , wherein the message including the information associated with allocation of the downlink resource is a downlink MAP message.

6. The method according to claim 1 , wherein the system information is transmitted by unicast.

7. An apparatus for receiving system information in a wireless communication system, the apparatus comprising: a transmitter; a receiver; and a processor configured to control the receiver to receive a message including information associated with allocation of a downlink resource with an Uplink Channel Description (UCD)/Downlink Channel Description (DCD) count from a base station and to receive changed system information through the allocated downlink resource when the UCD/DCD count is greater than a UCD/DCD count stored in the UE, and to receive a downlink data through the allocated downlink resource when the UCD/DCD count is the same as the UCD/DCD count stored in the UE, wherein the message is transmitted at the beginning of a listen interval of the UE.

8. The apparatus according to claim 7 , wherein the processor is configured to compare a UCD/DCD count value included in the message including the information associated with allocation of the downlink resource and a UCD/DCD count value stored in the apparatus and determines whether or not the system information has changed.

9. The apparatus according to claim 7 , wherein the processor is configured to control the transmitter to transmit negative-acknowledgement (NACK) information to the base station and configured to control the receiver to receive the changed system information from the base station, if the apparatus fails to receive the changed system information.

10. The apparatus according to claim 7 , wherein the changed system information is included in an Uplink Channel Description (UCD) message or a Downlink Channel Description (DCD) message.

11. The apparatus according to claim 7 , wherein the message including the information associated with allocation of the downlink resource is a downlink MAP message.

12. The apparatus according to claim 7 , wherein the system information is transmitted by unicast.

13. A method for transmitting system information by a base station in a wireless communication system, the method comprising: allocating a downlink resource and transmitting a message including information associated with the allocated downlink resource with Uplink Channel Description (UCD)/Downlink Channel Description (DCD) count to a User Equipment (UE); transmitting a message including changed system information through the allocated downlink resource when the UCD/DCD count is increased; and transmitting a downlink data through the allocated downlink resource when the UCD/DCD count is unchanged, wherein the message is transmitted at beginning of listen interval of the UE.

14. The method according to claim 13 , further comprising: receiving, from the UE, negative-acknowledgement (NACK) information indicating a failure of receiving the changed system information; and retransmitting the changed system information to the UE.

15. The method according to claim 13 , wherein the changed system information is included in an Uplink Channel Description (UCD) message or a Downlink Channel Description (DCD) message.

16. The method according to claim 13 , wherein the message including the information associated with the allocated downlink resource is a downlink MAP message.

17. An apparatus for transmitting system information in a wireless communication system, the apparatus comprising: a transmitter; a receiver; and a processor configured to allocate a downlink resource and configured to control the transmitter to transmit a message including information associated with the allocated downlink resource with an Uplink Channel Description (UCD)/Downlink Channel Description (DCD) count to a User Equipment (UE) and to transmit a message including changed system information through the allocated downlink resource when the UCD/DCD count is increased and to transmit a downlink data through the allocated downlink resource if the UCD/DCD count is unchanged, wherein the message is transmitted at the beginning of a listen interval of the UE.

18. The apparatus according to claim 17 , wherein the processor is configured to control the receiver to receive, from the UE, negative-acknowledgement (NACK) information indicating a failure of receiving the changed system information and to control the transmitter to retransmit the changed system information to the UE.

19. The apparatus according to claim 17 , wherein the changed system information is included in an Uplink Channel Description (UCD) message or a Downlink Channel Description (DCD) message.

20. The apparatus according to claim 17 , wherein the message including the information associated with the allocated downlink resource is a downlink MAP message.